The project started in 1992 and at the time of publication in 2000, golden rice was considered a significant breakthrough in
biotechnology as the researchers had engineered an entire Biosynthetic pathway.
The Leydig cells in some
species have been shown to possess the Biosynthetic machinery to manufacture testicular oxytocin de novo, to be specific,
in rats(which can synthesize vitamin C endogenously), and in guinea pigs, which, like humans, require an exogenous source of vitamin C(ascorbate) in their diets.